9 LED flashlight batteries question

[Ivan Vegvary]

Have a sh** load of the above. Get them free when shopping at Harbor Freight.
Lately, when batteries fail, I started checking with a voltmeter. Turns out that two of the three batteries always register circa 1.4 volts, while the third is about 0.6ą volts. Naturally, I started keeping the two higher voltage cells instead of trashing all three. Is this typical? Have I been needlessly wasting batteries this last 50 years? Never occurred to me to check voltages. BTW, these are all AAA cells.

Ivan Vegvary

 

[Michael A. Terrell]

Ivan Vegvary wrote:

Have a sh** load of the above. Get them free when shopping at Harbor Freight.
Lately, when batteries fail, I started checking with a voltmeter. Turns out that two of the three batteries always register circa 1.4 volts, while the third is about 0.6ą volts. Naturally, I started keeping the two higher voltage cells instead of trashing all three. Is this typical? Have I been needlessly wasting batteries this last 50 years? Never occurred to me to check voltages. BTW, these are all AAA cells.

Are you testing them under a load? Nine paralleled white LEDs use a
lot of current from those cheap Chinese AAA Carbon Zinc cells, so
unloaded readings are misleading.

 

[George Herold]

On May 30, 2:07 am, Ivan Vegvary <ivanvegv...@gmail.com> wrote:

Have a sh** load of the above.  Get them free when shopping at Harbor Freight.
Lately, when batteries fail, I started checking with a voltmeter.  Turns out that two of the three batteries always register circa 1.4 volts, while the third is about 0.6ą volts.  Naturally, I started keeping the two higher voltage cells instead of trashing all three.  Is this typical?  Have I been needlessly wasting batteries this last 50 years?  Never occurred to me to check voltages.  BTW, these are all AAA cells.

Ivan Vegvary

Maybe just cheap batteries. (?)
When you replace with new 'good' batteries do the cells discharge at
the same rate?

George H.

 

[Nobody]

On Wed, 29 May 2013 23:07:09 -0700, Ivan Vegvary wrote:

Have a sh** load of the above. Get them free when shopping at Harbor Freight.

Lately, when batteries fail, I started checking with a voltmeter. Turns
out that two of the three batteries always register circa 1.4 volts,
while the third is about 0.6Âą volts.

Weird.

Normally, an unloaded battery reads close to its nominal voltage
regardless of whether it's brand new or completely flat. The difference is
in the internal resistance, i.e. how quickly the voltage drops as the
current drawn increases.

 

[Bill Bowden]

On May 29, 11:07 pm, Ivan Vegvary <ivanvegv...@gmail.com> wrote:

Have a sh** load of the above.  Get them free when shopping at Harbor Freight.
Lately, when batteries fail, I started checking with a voltmeter.  Turns out that two of the three batteries always register circa 1.4 volts, while the third is about 0.6ą volts.  Naturally, I started keeping the two higher voltage cells instead of trashing all three.  Is this typical?  Have I been needlessly wasting batteries this last 50 years?  Never occurred to me to check voltages.  BTW, these are all AAA cells.

Ivan Vegvary

I usually check batteries by measuring short circuit current with a
DMM on the 10 amp range. Good alkalines read about 5 amps,
(D,C,AA,AAA) are all about the same. Carbon zincs read about half as
much, or 2 amps. Voltage is misleading, the acid test is short circuit
current.

-Bill

 

[Phil Allison]

"Ivan Vegvary"

Have a sh** load of the above. Get them free when shopping at Harbor
Freight.
Lately, when batteries fail, I started checking with a voltmeter. Turns out
that two of the three batteries always register circa 1.4 volts, while the
third is about 0.6ą volts. Naturally, I started keeping the two higher
voltage cells instead of trashing all three. Is this typical?

** Yes.

Very unlikely for three cells to be identical - one cell is likely to be the
weakest.

The effect seems to be worse when the load current is high - as in your
example.

Saw this over and over with groups of 4 x alkaline AAs used in RC receivers.

Why I changed to using NiCds.


..... Phil

 

[Phil Allison]

"Nobody"

" Lately, when batteries fail, I started checking with a voltmeter. Turns
out that two of the three batteries always register circa 1.4 volts,
while the third is about 0.6ą volts."

Weird.

** Not all all.

3.4 volts is where the LED torch begins to fade out - under load it will be
much less.

Normally, an unloaded battery reads close to its nominal voltage
regardless of whether it's brand new or completely flat.

** Absolute GARBAGE !!!

The difference is in the internal resistance,

** That is a separate fact.

Cell voltage does relate to remaining capacity fairly well and very well if
the cell is under its normal load.

Not true for rechargeable types though.



.... Phil

 

[Jamie]

Nobody wrote:

On Wed, 29 May 2013 23:07:09 -0700, Ivan Vegvary wrote:


Have a sh** load of the above. Get them free when shopping at Harbor Freight.


Lately, when batteries fail, I started checking with a voltmeter. Turns
out that two of the three batteries always register circa 1.4 volts,
while the third is about 0.6Âą volts.


Weird.

Normally, an unloaded battery reads close to its nominal voltage
regardless of whether it's brand new or completely flat. The difference is
in the internal resistance, i.e. how quickly the voltage drops as the
current drawn increases.

Really? sounds a little bogus to me.. Since i've seen a good many
cells exhibit low voltage after drain.

If you are referring to rechargeable's, that could be a different story.

Jamie

 

[Steve Gonedes]

Ivan Vegvary <ivanvegvary@gmail.com> writes:

< Lately, when batteries fail, I started checking with a voltmeter. Turns out
< that two of the three batteries always register circa 1.4 volts, while the
< third is about 0.6Âą volts. Naturally, I started keeping the two higher

[ ... ]

I had the same problem with my microcontroller. The nine-volt battery
tested o.k. but The pic-micro "needs" 9 volts to operate. I was sampling
light with a phototransistor... my aunt figured it. She said your
batteries are probably dead.

I had the other problem of trying to run the micro at 9 volts while
using a LCD display. The blocks on the LCD went all black - I started
using an adjustable wall-wart plug in transformer. Set it 7.5v and all
went well. Took me several years to figure to ask my little cousin who
figured that one...

< voltage cells instead of trashing all three. Is this typical? Have I been
< needlessly wasting batteries this last 50 years? Never occurred to me to
< check voltages. BTW, these are all AAA cells.

Some times rotating the batteries works.

 

[Ian Field]

"Ivan Vegvary" <ivanvegvary@gmail.com> wrote in message
news:8b97b4fc-d498-4dbb-9e3b-689da2458940@googlegroups.com...

Have a sh** load of the above. Get them free when shopping at Harbor
Freight.
Lately, when batteries fail, I started checking with a voltmeter. Turns
out that two of the three batteries always register circa 1.4 volts, while
the third is about 0.6ą volts. Naturally, I started keeping the two
higher voltage cells instead of trashing all three. Is this typical?
Have I been needlessly wasting batteries this last 50 years?

They probably wouldn't be giving them away free if the batteries in them
were any good.

 

[Uncle Steve]

On Sat, Jun 01, 2013 at 08:53:01PM -0400, Michael Black wrote:

On Sat, 1 Jun 2013, Ian Field wrote:



"Ivan Vegvary" <ivanvegvary@gmail.com> wrote in message
news:8b97b4fc-d498-4dbb-9e3b-689da2458940@googlegroups.com...
Have a sh** load of the above. Get them free when shopping at Harbor
Freight.
Lately, when batteries fail, I started checking with a voltmeter. Turns
out that two of the three batteries always register circa 1.4 volts,
while the third is about 0.6ą volts. Naturally, I started keeping the
two higher voltage cells instead of trashing all three. Is this typical?
Have I been needlessly wasting batteries this last 50 years?

They probably wouldn't be giving them away free if the batteries in them
were any good.

I don't know. IN the old days "batteries not icluded" wsa pretty normal,
but most things I've bought in recent years did have batteries when
applicable. And I find the batteries generally fairly good. Not
noticeably bad.

I don't know where the pricing comes from. I keep buying LED flashlights
(torches in some countries), and they come with batteries. And then it
often seems to make sense to buy a new one when the batteries do die out
An exaggeration, but I keep buying the LED flashlights because they keep
adding LEDs to them, making them brighter.

FOr that matter, I've needed button cells to replace worn out button cells
in various things, and for those that need the size, it's cheaper to buy a
99cent or $1.49 laser pointer for the batteries than buy the button cells
separately. Yes, you can get the cells cheap in some circles, but
generally not as handy as where the laser pointers get sold.

Ironically, the one LED flashlight that I care most about is faulty. I
have a 2AA Maglite, and a few years back got an LED replacement bulb,
which worked fine, but now has gotten flakey. I'm not sure if it's the
contacts, the LED module, or the Maglite. Ironic since the Maglite wasn't
cheap, and neither was the LED replacement, but the cheap LED flashlights
generally are fine.

I hate flashlights that use button cells. While LR44 or 2CR2025 cells
are relatively inexpensive, they really don't have a lot of capacity.
I have a 2AA maglite and a Fizer I-Beam X1 which takes 1 AA. I used
to have a Gerber "Infinity Ultra Task Light" 22-80010, but someone
stole it; 60+ hours on one AA. Button-cell flashlights are for day-
outings.


Regards,

Uncle Steve

--
There should be a special word in the English language to identify
people who create problems and then turn around and offer up their own
tailor-made bogus non-solutions designed to completely avoid the root
causes of the situation under consideration. 'Traitor' might be a
good choice, but lacks the requisite specificity. One of the problems
with contemporary English is it lacks many such words that would
otherwise categorically identify certain kinds of person, place, or
thing -- making it difficult or impossible to think analytically about
such objects. These shortcomings of the English lexicon are
representative of Orwellian linguistics at work in the real world.

 

[Michael Black]

On Sat, 1 Jun 2013, Uncle Steve wrote:

I hate flashlights that use button cells. While LR44 or 2CR2025 cells
are relatively inexpensive, they really don't have a lot of capacity.
I have a 2AA maglite and a Fizer I-Beam X1 which takes 1 AA. I used
to have a Gerber "Infinity Ultra Task Light" 22-80010, but someone
stole it; 60+ hours on one AA. Button-cell flashlights are for day-
outings.


Actually my need for button cells is for that kitchen timer I have lying

her waiting for a battery. I've bought laser pointers for the button
cells for those kitchen timers before, I think I got an analog battery
operated clock going with a button cell from a laser pointer too.

I also have a battery powered pocket watch that needs a new battery. WHen
I finally got the back cover off, I discovered it used "button cells" like
you find in computers, CR2026 or whatever, for the built in LED
flashlight, which still works fine (it used a red LED, so I never used it
that much). But the clock runs off a separate battery, and that one is
smaller, I think smaller than the laser pointer batteries. SO that too
sits opened, waiting for me to get around to looking for a suitable
battery.

Michael

 

[Bob Masta]

On Sat, 1 Jun 2013 23:53:00 -0400, Michael Black
<et472@ncf.ca> wrote:

Actually my need for button cells is for that kitchen timer I have lying
her waiting for a battery. I've bought laser pointers for the button
cells for those kitchen timers before, I think I got an analog battery
operated clock going with a button cell from a laser pointer too.

For certain items like kitchen timers, clocks, and
calculators I often use a trick: Old 9V batteries from
smoke detectors, etc, still have a lot of juice left when
they are no longer useful in their original application (at
least compared to the low-voltage trickle needed by LCD
display devices). I build a tiny voltage regulator using a
couple of NPNs and LEDs (forward biased through a high R to
serve as a sharp-cutoff Vref). The whole works can be
soldered together on top of a 9V battery clip, though I've
also made tiny PCBs from scraps.

The result is that the 9V battery typically powers the
device for a year or 2, at least, before it can't maintain
the 3V needed for the device. By then I've usually
collected plenty more 9V batteries. Snap the old one out
and the new one in!

Of course, the Frankenstein timer/clock/whatever with a
hulking 9V battery strapped to it is not likely to appeal to
anyone with delicate sensitivities or fine aesthetic sense
(or maybe *any* aesthetic sense!), but I get a kick out of
the whole idea of running it "for free".

Best regards,


Bob Masta

DAQARTA v7.21
Data AcQuisition And Real-Time Analysis
www.daqarta.com
Scope, Spectrum, Spectrogram, Sound Level Meter
Frequency Counter, Pitch Track, Pitch-to-MIDI
FREE Signal Generator, DaqMusic generator
Science with your sound card!

 

[Michael Black]

On Sun, 2 Jun 2013, Bob Masta wrote:

On Sat, 1 Jun 2013 23:53:00 -0400, Michael Black
et472@ncf.ca> wrote:

Actually my need for button cells is for that kitchen timer I have lying
her waiting for a battery. I've bought laser pointers for the button
cells for those kitchen timers before, I think I got an analog battery
operated clock going with a button cell from a laser pointer too.

For certain items like kitchen timers, clocks, and
calculators I often use a trick: Old 9V batteries from
smoke detectors, etc, still have a lot of juice left when
they are no longer useful in their original application (at
least compared to the low-voltage trickle needed by LCD
display devices). I build a tiny voltage regulator using a
couple of NPNs and LEDs (forward biased through a high R to
serve as a sharp-cutoff Vref). The whole works can be
soldered together on top of a 9V battery clip, though I've
also made tiny PCBs from scraps.

I once bought a nice LCD clock for a couple of dollars, it was nice

because the readout was larger than what I'd found at that price level.
And when the button cell wore out, I didn't even bother looking for a
button cell, I just soldered in an AA battery, hanging it off the back.
The AA battery does last forever, I can't remember when I soldered in the
first one, but it was at least a decade ago, and I've replaced it once,
and it keeps on ticking.

I guess I wanted the kitchen timer to be more portable.

And yes, I do change the smoke detectors after a year or so, and thus the
"old" batteries get used for something else, that isn't as important, so
the smoke detectors run fine but the batteries aren't wasted.

Michael

 

[Jim Thompson]

On Sat, 01 Jun 2013 23:13:54 -0400, Uncle Steve <stevet810@gmail.com>
wrote:

On Sat, Jun 01, 2013 at 08:53:01PM -0400, Michael Black wrote:
On Sat, 1 Jun 2013, Ian Field wrote:



"Ivan Vegvary" <ivanvegvary@gmail.com> wrote in message
news:8b97b4fc-d498-4dbb-9e3b-689da2458940@googlegroups.com...
Have a sh** load of the above. Get them free when shopping at Harbor
Freight.
Lately, when batteries fail, I started checking with a voltmeter. Turns
out that two of the three batteries always register circa 1.4 volts,
while the third is about 0.6ą volts. Naturally, I started keeping the
two higher voltage cells instead of trashing all three. Is this typical?
Have I been needlessly wasting batteries this last 50 years?

They probably wouldn't be giving them away free if the batteries in them
were any good.

I don't know. IN the old days "batteries not icluded" wsa pretty normal,
but most things I've bought in recent years did have batteries when
applicable. And I find the batteries generally fairly good. Not
noticeably bad.

I don't know where the pricing comes from. I keep buying LED flashlights
(torches in some countries), and they come with batteries. And then it
often seems to make sense to buy a new one when the batteries do die out
An exaggeration, but I keep buying the LED flashlights because they keep
adding LEDs to them, making them brighter.

FOr that matter, I've needed button cells to replace worn out button cells
in various things, and for those that need the size, it's cheaper to buy a
99cent or $1.49 laser pointer for the batteries than buy the button cells
separately. Yes, you can get the cells cheap in some circles, but
generally not as handy as where the laser pointers get sold.

Ironically, the one LED flashlight that I care most about is faulty. I
have a 2AA Maglite, and a few years back got an LED replacement bulb,
which worked fine, but now has gotten flakey. I'm not sure if it's the
contacts, the LED module, or the Maglite. Ironic since the Maglite wasn't
cheap, and neither was the LED replacement, but the cheap LED flashlights
generally are fine.

I hate flashlights that use button cells. While LR44 or 2CR2025 cells
are relatively inexpensive, they really don't have a lot of capacity.
I have a 2AA maglite and a Fizer I-Beam X1 which takes 1 AA. I used
to have a Gerber "Infinity Ultra Task Light" 22-80010, but someone
stole it; 60+ hours on one AA. Button-cell flashlights are for day-
outings.


Regards,

Uncle Steve

Naaaah! Button cells are for my pocket Nano Light, for occasional
use, to peer into a mailbox after dark, etc.

...Jim Thompson
--
| James E.Thompson | mens |
| Analog Innovations | et |
| Analog/Mixed-Signal ASIC's and Discrete Systems | manus |
| San Tan Valley, AZ 85140 Skype: Contacts Only | |
| Voice480)460-2350 Fax: Available upon request | Brass Rat |
| E-mail Icon at http://www.analog-innovations.com | 1962 |

I love to cook with wine. Sometimes I even put it in the food.

 

[Ian Field]

"Michael Black" <et472@ncf.ca> wrote in message
news:alpine.LNX.2.02.1306012048120.23715@darkstar.example.org...

On Sat, 1 Jun 2013, Ian Field wrote:



"Ivan Vegvary" <ivanvegvary@gmail.com> wrote in message
news:8b97b4fc-d498-4dbb-9e3b-689da2458940@googlegroups.com...
Have a sh** load of the above. Get them free when shopping at Harbor
Freight.
Lately, when batteries fail, I started checking with a voltmeter. Turns
out that two of the three batteries always register circa 1.4 volts,
while
the third is about 0.6ą volts. Naturally, I started keeping the two
higher
voltage cells instead of trashing all three. Is this typical? Have I
been
needlessly wasting batteries this last 50 years?

They probably wouldn't be giving them away free if the batteries in them
were
any good.

I don't know. IN the old days "batteries not icluded" wsa pretty normal,
but most things I've bought in recent years did have batteries when
applicable. And I find the batteries generally fairly good. Not
noticeably bad.

I don't know where the pricing comes from. I keep buying LED flashlights
(torches in some countries), and they come with batteries. And then it
often seems to make sense to buy a new one when the batteries do die out
An exaggeration, but I keep buying the LED flashlights because they keep
adding LEDs to them, making them brighter.

FOr that matter, I've needed button cells to replace worn out button cells
in various things, and for those that need the size, it's cheaper to buy a
99cent or $1.49 laser pointer for the batteries than buy the button cells
separately. Yes, you can get the cells cheap in some circles, but
generally not as handy as where the laser pointers get sold.

Just lately we've had numerous discount stores spring up all over the place
like Poundland where everything is 1 GBP, usually there's quite a few places
you can buy a card of button or coin cells for around Ł1. IIRC the button
cells are about 30 in assorted sizes per card, the coin cells are only 8 -
4x 2032, 2x 2025 & 2x 2016.

The coin cells mostly go in the outside temperature sender for my desk
clock-thermometer, they don't last quite as long as the expensive named
brand ones, but at that price, who cares.

 

[Ian Field]

"Uncle Steve" <stevet810@gmail.com> wrote in message
news:d27870280279f22-6d9fe@gmail.com...

On Sat, Jun 01, 2013 at 08:53:01PM -0400, Michael Black wrote:
On Sat, 1 Jun 2013, Ian Field wrote:



"Ivan Vegvary" <ivanvegvary@gmail.com> wrote in message
news:8b97b4fc-d498-4dbb-9e3b-689da2458940@googlegroups.com...
Have a sh** load of the above. Get them free when shopping at Harbor
Freight.
Lately, when batteries fail, I started checking with a voltmeter.
Turns
out that two of the three batteries always register circa 1.4 volts,
while the third is about 0.6ą volts. Naturally, I started keeping the
two higher voltage cells instead of trashing all three. Is this
typical?
Have I been needlessly wasting batteries this last 50 years?

They probably wouldn't be giving them away free if the batteries in them
were any good.

I don't know. IN the old days "batteries not icluded" wsa pretty normal,
but most things I've bought in recent years did have batteries when
applicable. And I find the batteries generally fairly good. Not
noticeably bad.

I don't know where the pricing comes from. I keep buying LED flashlights
(torches in some countries), and they come with batteries. And then it
often seems to make sense to buy a new one when the batteries do die out
An exaggeration, but I keep buying the LED flashlights because they keep
adding LEDs to them, making them brighter.

FOr that matter, I've needed button cells to replace worn out button
cells
in various things, and for those that need the size, it's cheaper to buy
a
99cent or $1.49 laser pointer for the batteries than buy the button cells
separately. Yes, you can get the cells cheap in some circles, but
generally not as handy as where the laser pointers get sold.

Ironically, the one LED flashlight that I care most about is faulty. I
have a 2AA Maglite, and a few years back got an LED replacement bulb,
which worked fine, but now has gotten flakey. I'm not sure if it's the
contacts, the LED module, or the Maglite. Ironic since the Maglite
wasn't
cheap, and neither was the LED replacement, but the cheap LED flashlights
generally are fine.

I hate flashlights that use button cells. While LR44 or 2CR2025 cells
are relatively inexpensive, they really don't have a lot of capacity.
I have a 2AA maglite and a Fizer I-Beam X1 which takes 1 AA. I used
to have a Gerber "Infinity Ultra Task Light" 22-80010, but someone
stole it; 60+ hours on one AA. Button-cell flashlights are for day-
outings.

These days I avoid any flashlight that isn't LED, I make the further
distinction that it should be a 2 cell design, as this requires an inverter
to make the LED Vf. Many 3 cell LED lamps I've seen don't even have a
current limiting resistor - instead relying on the cell's internal
resistance to protect the LED.

If I saw a pricey 3D lamp - it might have a buck/boost converter - but I'd
check the small print before parting with any cash!

 

[Ian Field]

"Bob Masta" <N0Spam@daqarta.com> wrote in message
news:51ab3b5c.278638@news.eternal-september.org...

On Sat, 1 Jun 2013 23:53:00 -0400, Michael Black
et472@ncf.ca> wrote:

Actually my need for button cells is for that kitchen timer I have lying
her waiting for a battery. I've bought laser pointers for the button
cells for those kitchen timers before, I think I got an analog battery
operated clock going with a button cell from a laser pointer too.

For certain items like kitchen timers, clocks, and
calculators I often use a trick: Old 9V batteries from
smoke detectors, etc, still have a lot of juice left when
they are no longer useful in their original application (at
least compared to the low-voltage trickle needed by LCD
display devices). I build a tiny voltage regulator using a
couple of NPNs and LEDs (forward biased through a high R to
serve as a sharp-cutoff Vref). The whole works can be
soldered together on top of a 9V battery clip,

You could tidy up your uPower regulator quite a bit - pry the end out of a
metal jacket 9V battery and shake out the cluster of cells - you now have a
neat little case to build in.

Strip 2 batteries and you can re-assemble the metal jacket with a connector
clip at both ends, one end is the low battery in and regulated out at the
other - soldering to the out terminals avoids any future confusion about
which end is which.

 

[Jamie]

Jim Thompson wrote:

On Sat, 01 Jun 2013 23:13:54 -0400, Uncle Steve <stevet810@gmail.com
wrote:


On Sat, Jun 01, 2013 at 08:53:01PM -0400, Michael Black wrote:

On Sat, 1 Jun 2013, Ian Field wrote:



"Ivan Vegvary" <ivanvegvary@gmail.com> wrote in message
news:8b97b4fc-d498-4dbb-9e3b-689da2458940@googlegroups.com...

Have a sh** load of the above. Get them free when shopping at Harbor
Freight.
Lately, when batteries fail, I started checking with a voltmeter. Turns
out that two of the three batteries always register circa 1.4 volts,
while the third is about 0.6ą volts. Naturally, I started keeping the
two higher voltage cells instead of trashing all three. Is this typical?
Have I been needlessly wasting batteries this last 50 years?

They probably wouldn't be giving them away free if the batteries in them
were any good.


I don't know. IN the old days "batteries not icluded" wsa pretty normal,
but most things I've bought in recent years did have batteries when
applicable. And I find the batteries generally fairly good. Not
noticeably bad.

I don't know where the pricing comes from. I keep buying LED flashlights
(torches in some countries), and they come with batteries. And then it
often seems to make sense to buy a new one when the batteries do die out
An exaggeration, but I keep buying the LED flashlights because they keep
adding LEDs to them, making them brighter.

FOr that matter, I've needed button cells to replace worn out button cells
in various things, and for those that need the size, it's cheaper to buy a
99cent or $1.49 laser pointer for the batteries than buy the button cells
separately. Yes, you can get the cells cheap in some circles, but
generally not as handy as where the laser pointers get sold.

Ironically, the one LED flashlight that I care most about is faulty. I
have a 2AA Maglite, and a few years back got an LED replacement bulb,
which worked fine, but now has gotten flakey. I'm not sure if it's the
contacts, the LED module, or the Maglite. Ironic since the Maglite wasn't
cheap, and neither was the LED replacement, but the cheap LED flashlights
generally are fine.

I hate flashlights that use button cells. While LR44 or 2CR2025 cells
are relatively inexpensive, they really don't have a lot of capacity.
I have a 2AA maglite and a Fizer I-Beam X1 which takes 1 AA. I used
to have a Gerber "Infinity Ultra Task Light" 22-80010, but someone
stole it; 60+ hours on one AA. Button-cell flashlights are for day-
outings.


Regards,

Uncle Steve


Naaaah! Button cells are for my pocket Nano Light, for occasional
use, to peer into a mailbox after dark, etc.

...Jim Thompson
Ah, so that's you I see out at night rooming the streets?

Jamie

 

[Ian Field]

"Michael Black" <et472@ncf.ca> wrote in message
news:alpine.LNX.2.02.1306020934490.25026@darkstar.example.org...

On Sun, 2 Jun 2013, Bob Masta wrote:

On Sat, 1 Jun 2013 23:53:00 -0400, Michael Black
et472@ncf.ca> wrote:

Actually my need for button cells is for that kitchen timer I have lying
her waiting for a battery. I've bought laser pointers for the button
cells for those kitchen timers before, I think I got an analog battery
operated clock going with a button cell from a laser pointer too.

For certain items like kitchen timers, clocks, and
calculators I often use a trick: Old 9V batteries from
smoke detectors, etc, still have a lot of juice left when
they are no longer useful in their original application (at
least compared to the low-voltage trickle needed by LCD
display devices). I build a tiny voltage regulator using a
couple of NPNs and LEDs (forward biased through a high R to
serve as a sharp-cutoff Vref). The whole works can be
soldered together on top of a 9V battery clip, though I've
also made tiny PCBs from scraps.

I once bought a nice LCD clock for a couple of dollars, it was nice
because the readout was larger than what I'd found at that price level.
And when the button cell wore out, I didn't even bother looking for a
button cell, I just soldered in an AA battery, hanging it off the back.
The AA battery does last forever, I can't remember when I soldered in the
first one, but it was at least a decade ago, and I've replaced it once,
and it keeps on ticking.

I guess I wanted the kitchen timer to be more portable.

And yes, I do change the smoke detectors after a year or so, and thus the
"old" batteries get used for something else, that isn't as important, so
the smoke detectors run fine but the batteries aren't wasted.

About a decade ago a local pharmacy had a clearance sale of smoke detectors
at only UK 99p each - so I bought quite a few. Unfortunately they seemed to
lose their sensitivity after a few months (maybe because I was a heavy
smoker at the time) - meanwhile the landlord decided to install rechargeable
mains smoke alarms to all their properties, so I was left with a quantity of
good quality batteries, battery clips, very loud piezo sounders & LEDs that
had only cos 99p per set.